The present invention relates generally to pumps and more particularly to pumping apparatus for pumping fluent materials, such as concrete.
With the recent emphasis on the use of concrete for high-rise building structures, various pumps have been proposed for transporting a plastic mass, such as concrete, through some type of portable pumping unit.
One type of pumping unit that has been used for this purpose includes a hopper for receiving concrete from a source with a delivery line leading from the hopper. A pair of cylinders with pistons reciprocated therein communicate with the hopper and a shuttle valve is located between the cylinders and the delivery line. The pistons for the respective cylinders are driven in opposite directions and one cylinder is connected to the delivery line while the other cylinder is in communication with the hopper. With such an arrangement, concrete is being withdrawn from the hopper into one cylinder while the concrete in the second cylinder is being forced out into the delivery line.